The present invention relates to a vehicle, more particularly to the design of an axle carrier of the vehicle. The vehicle is more particularly designed as a motor vehicle with four wheels.
German patent document DE 10 2005 017 031 A1 discloses, by way of example, an axle carrier according to the prior art. Normally axle carriers, more particularly rear axle carriers, are designed completely self-supporting and are connected to the vehicle via several rubber bearings. This serves primarily for the acoustic decoupling of the rear axle transmission in the case of vehicles driven by combustion engines. Both the body and also the axle carrier must thereby be designed completely self-supporting in order to be sufficiently rigid and operationally reliable in spite of the rubber elements which connect them together. This requires corresponding weight.
It is the object of the present invention to provide a vehicle which with a cost-effective construction and a low-maintenance operation is to have the lightest weight possible and at the same time sufficient fatigue strength.
This and other objects are achieved by a vehicle, more particularly a motor vehicle, comprising a body, a flat component arranged under the body, and at least one axle carrier arrangement. The axle carrier arrangement is provided either for the two front or the two rear wheel suspensions. The axle carrier arrangement is, more particularly, designed for the rear axle. The axle carrier arrangement comprises a left-hand and a right-hand suspension arm bracket. The two suspension arm brackets each serve for connecting at least one suspension arm of one wheel suspension. One wheel each can be mounted on each left-hand and right-hand wheel suspension. According to the invention, the two suspension arm brackets are each fastened on the body and on the flat component. The two suspension arm brackets are correspondingly situated between the body and the flat component. Furthermore, a center suspension arm bracket is provided. The center suspension arm bracket is also called a cross structure. In particular, the center suspension arm bracket is located, seen in the driving direction, behind the left-hand and right-hand suspension arm bracket. The center suspension arm bracket serves to connect at least one suspension arm of the left-hand wheel suspension and at least one suspension arm of the right-hand wheel suspension. The center suspension arm bracket is also fixed on the body and on the flat component and is thus situated between the body and the flat component. The three suspension arm brackets, thus the left-hand suspension arm bracket, the right-hand suspension arm bracket and the center suspension arm bracket, are three separate component parts which are not directly connected. The three suspension arm brackets taken by themselves do not form a supporting structure. Only the connection of the three suspension arm brackets to the body and to the flat component leads to a supporting structure on which the wheel suspensions can be connected by way of the suspension arms. No cross support is provided between the left-hand and right-hand suspension arm bracket. An indirect connection of the suspension arm brackets is only achieved by the body and by the flat component.
According to the invention, at least one of the suspension arm brackets includes a bearing for an electric machine driving the vehicle. More particularly, each of the three suspension arm brackets has one bearing each so that the electric machine is accommodated at three points between the three suspension arm brackets. A decisive advantage of the invention is that a relatively large structural space remains between the three suspension arm brackets. A corresponding electric machine, even with transmission and differential, can be easily arranged in this structural space. The vehicle is accordingly preferably designed as a hybrid vehicle or electric vehicle.
According to the invention there is no separate self-supporting structure such as, by way of example, a body and a self-supporting rear axle carrier. Within the scope of the invention it was recognized that no self-supporting axle carrier is necessary if a corresponding flat component is bound into the complete supporting structure. A considerable weight and cost saving is thereby achieved for the vehicle.
Advantageous developments of the suspension arm brackets are described below. The development is thereby provided in each case for at least one of the three suspension arm brackets.
It is preferred that at least one of the suspension arm brackets is connected rigidly to the body. It is furthermore preferred that at least one of the suspension arm brackets is connected rigidly to the flat component. The rigid connection is thereby preferably undertaken by screws. More particularly, rubber-elastic bearings are omitted for the rigid connection. By using correspondingly good rubber bearings between the suspension arms and the suspension arm brackets, the suspension arm brackets can be rigidly connected to the flat component and/or to the body.
The flat component is preferably designed to be structurally reinforcing. This means that the axle carrier arrangement is only load-bearing by fastening the suspension arm brackets on the flat component and on the body. The entire structure is thus only load-bearing by screwing the individual components to one another and to the body.
The flat component is preferably designed as an underbody. More particularly, this underbody forms a lower aerodynamic closure of the vehicle. The flat component is thus not only a shear panel, but also serves at the same time as an underbody, more particularly for improving the aerodynamics of the vehicle. According to the invention the flat component is required in order to form together with the suspension arm brackets and the body, one supporting structure. Therefore, an operation of the vehicle without the flat component, more particularly without the underbody, is not possible. The formation of the underbody as an aerodynamic closure of the vehicle enables an energy-efficient operation of the vehicle, and thus more particularly an extended range. In the prior art the axle suspension is movable relative to the body through a rubber-elastic connection. Therefore in the prior art fixing a closed underbody, which is secured to the vehicle, on the axle carrier is not possible without further measures. According to the invention this is however possible since the suspension arm brackets and thus also the flat component are connectable rigidly to the body.
It is preferred if the flat component is connected non-destructively releasably to all three suspension arm brackets. The non-destructively releasable connection is achieved more particularly by screw fastenings. Thus, in particular, the flat component designed as the underbody can be dismantled and reassembled again with minimum effort for maintenance purposes. More particularly when arranging a motor preferably an electric motor between the suspension arm brackets, the motor is directly accessible by dismantling the underbody.
It is furthermore preferred that the body is connected, preferably screwed, in a non-destructive releasable manner to all three suspension arm brackets. A simple mounting and dismantling is provided by this releasable connection. Furthermore, different materials can be connected to one another without problem by the screw fitting.
The flat component, more particularly designed as an underbody, is preferably connected, preferably screwed, in a non-destructive releasable manner to the body at at least one body attachment point. In order to design the dismantling capability and thus the accessibility to the motor as best as possible, the underbody should also be non-destructively releasable from the body.
The flat component, more particularly designed as an underbody, is preferably so large that it engages partially round the wheels. Recesses are provided accordingly in the flat component for the wheels of the vehicle.
The flat component is more particularly not only a small shear panel within the axle carrier, but also preferably extends over at least 10%, preferably at least over 20%, more particularly preferably at least over 30%, of the surface area of a vertical projection of the vehicle.
The flat component is preferably made up of a plate element and a reinforcement structure reinforcing the plate element. The reinforcement structure is set on the plate element or is integrated in the plate element. More particularly, the plate element is formed thicker in some places wherein the thick portions form the reinforcement structure.
Particularly preferred is for the plate element to be a sandwich structure. Through different thickness core material, e.g. foam or honeycomb structure, the reinforcement structure can be integrated directly into the plate element.
More particularly, the complete flat component has a maximum thickness of 150 mm, preferably 50 mm, more particularly preferred 20 mm, so that sufficient structural space is provided above the flat component and sufficient ground clearance is provided underneath the flat component.
The center suspension arm bracket is preferably connected at two connection points to the flat component and to two body attachment points to the body, wherein the center suspension arm bracket is configured at least approximately free of bending moment relative to these four force introduction points (two connection points and two body attachment points). The configuration free of bending moment applies in the first instance for forces perpendicular to the longitudinal direction of the vehicle. This is preferably achieved as follows: two imaginary lines (secondary lines) each run, corresponding to the force paths, through a body attachment point and the diagonally opposite connection point. Material of the center suspension arm bracket is provided along these two lines, i.e. there are no, or only slight, recesses provided on these lines. For an at least approximately bending-moment-free configuration it is preferably proposed that material is provided over at least 50%, preferably at least 60%, of the overall length of these lines. It is furthermore proposed that material is provided at the intersection point of the two lines.
The different component parts of the envisaged vehicle can be made from metal. Alternatively it is proposed advantageously to manufacture at least one of the suspension arm brackets and/or the flat component from a pressed composite material or a fiber-composite material. More particularly fiber-reinforced plastic is used as the fiber-composite material. Furthermore it is proposed to combine the fiber-composite materials and the pressed composite materials with one another.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.